Vetdrugs 2.0Dexmedetomidine is a selective alpha2-adrenergic agonist and the pharmacologically active enantiomer of medetomidine. It is used in dogs and cats for sedation, analgesia and anesthetic premedication. A lower-dose oromucosal gel has a distinct role in reducing acute noise-associated fear and anxiety in dogs. Injectable dexmedetomidine also has an extra-label role in feline emesis induction.
Group
Alpha-2 adrenergic agonist
Mechanism of Action
Dexmedetomidine stimulates central alpha2-adrenergic receptors, reducing norepinephrine release and sympathetic neurotransmission. Suppression of arousal pathways produces sedation and anxiolysis, while spinal and supraspinal effects reduce nociceptive transmission and provide analgesia. The balance between anxiolysis and sedation depends on exposure. Activation of alpha2 receptors in emetic pathways can trigger vomiting in cats, accounting for its emetic use.
Dose Rates
Dog
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Premedication | Reference only | IM | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia; 125 mcg/m²; requires body-surface-area dosing. Do not substitute a fixed mg/kg equivalent across dog sizes. | |
| Sedation and analgesia | Reference only | IV | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia; 375 mcg/m²; requires body-surface-area dosing. Do not substitute a fixed mg/kg equivalent across dog sizes. | |
| Sedation and analgesia | Reference only | IM | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia; 500 mcg/m²; requires body-surface-area dosing. Do not substitute a fixed mg/kg equivalent across dog sizes. | |
| Noise aversion | Reference only | OTM | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia; Sileo: 125 mcg/m² using the calibrated product dosing chart. Apply 30–60 minutes before the event or when signs begin; repeat only if needed at intervals of at least 2 hours, no more than 5 doses per event. Do not redose a sedated dog. | |
| Combination anesthesia | Reference only | IM | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia; Ketamine 3 mg/kg + dexmedetomidine 15 mcg/kg + buprenorphine 40 mcg/kg in a single injection; combination protocol. | |
| Postoperative analgesia infusion | Reference only | IV | Study regimen: 25 mcg/m² IV loading dose followed by 25 mcg/m²/hour for 24 hours. Approximately half the dogs required rescue morphine 0.2 mg/kg IV. Body-surface-area infusion is unsupported by the calculator. | |
| Body-surface-area combination anesthesia | Reference only | IM | Equal volumes of dexmedetomidine 0.5 mg/mL, ketamine 100 mg/mL and one opioid: butorphanol 10 mg/mL, hydromorphone 2 mg/mL, morphine 15 mg/mL or buprenorphine 0.3 mg/mL. Dexmedetomidine targets: 62.5 mcg/m² for geriatric/organ-dysfunction premedication, 125 for light procedures, 250 for minor surgery or marked relaxation, 375 for surgical induction, and 500 for extreme fractiousness. IV use is also described for the first four levels. These concentration-dependent alternatives require a complete anesthetic plan. |
Cat
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Sedation | 40 mcg/kg | IM | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia | |
| Sedation | 10–25 mcg/kg | IM | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia; Lower-dose alternative for shorter procedures or adjunctive use. | |
| Sedation | 5–20 mcg/kg | IV | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia | |
| Sedation | 20–40 mcg/kg | OTM | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia; Injectable solution applied to oral mucosa; distinct from the low-concentration gel. | |
| Anxiolysis | 5 mcg/kg | OTM | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia; Oral mucosal gel; do not substitute the source’s fixed per-cat volume for a weight-based amount. | |
| Emesis induction | 10 mcg/kg | IM | Once | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia |
| Combination sedation | Reference only | IM | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia; Examples: dexmedetomidine 20 mcg/kg + ketamine 3–5 mg/kg; dexmedetomidine 10 mcg/kg + butorphanol 0.2 mg/kg; dexmedetomidine 20 mcg/kg + alfaxalone 2 mg/kg. Another protocol combines dexmedetomidine 10 mcg/kg + ketamine 5 mg/kg with butorphanol 0.2–0.4 mg/kg or buprenorphine 0.03 mg/kg. A 40 mcg/kg dexmedetomidine plus 5 mg/kg ketamine preanesthetic protocol is also reported. | |
| Sedation infusion — Loading | 3–10 mcg/kg | IM | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia | |
| Sedation infusion — Maintenance | 1 mcg/kg/hour | IV | Continuous | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia |
| Concentration-specific triple sedation | Reference only | IM | Use equal volumes of EACH component: dexmedetomidine 0.5 mg/mL, ketamine 100 mg/mL, and one opioid at butorphanol 10 mg/mL, hydromorphone 2 mg/mL, morphine 15 mg/mL or buprenorphine 0.3 mg/mL. Source weight bands and per-component volumes for mild / moderate / profound effect: 2–3 kg: 0.025 / 0.05 / 0.1–0.15 mL; 3–4 kg: 0.05 / 0.1 / 0.2–0.25 mL; 4–6 kg: 0.1 / 0.2 / 0.3–0.35 mL; 6–7 kg: 0.2 / 0.3 / 0.4–0.45 mL; 7–8 kg: 0.3 / 0.4 / 0.5–0.55 mL. Adjacent source bands share endpoints, and effect/category selection is procedural; this is not a single-agent calculator regimen. |
Horse
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Surgical sedation — Loading | 5 mcg/kg | IV | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia | |
| Surgical sedation — Maintenance | 8 mcg/kg/hour | IV | Continuous | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia |
| Perioperative analgesia | 1.75–2 mcg/kg/hour | IV | Continuous | Do not use in: Shock, Pre-existing hypotension, hypoxia or bradycardia |
Indications
- Sedation and analgesia in dogs and cats for examinations, diagnostic investigations and selected minor procedures.
- Preanesthetic medication and adjunctive use in balanced anesthesia protocols in dogs and cats.
- Treatment of acute noise aversion in dogs with the corresponding oromucosal gel formulation.
- Extra-label induction of emesis in selected cats following an ingestion for which gastrointestinal decontamination is indicated.
Contraindications
- Shock, hypotension, hypoxia or pre-existing bradycardia
- Use cautiously with cardiac, respiratory, hepatic or renal disease and pregnancy.
Interactions
- Opioids and other anesthetics enhance depression and usually require lower doses.
- Concurrent atropine may worsen hypertension and arrhythmias.
Adverse effects
- Vomiting
- Bradycardia, hypertension followed by hypotension, arrhythmias
- Hypothermia and respiratory depression
- Paradoxical excitement
Toxicity
Excessive sedation and cardiovascular depression require airway support, monitoring and appropriate alpha-2 reversal.
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Dexmedetomidine hydrochloride 0.5 mg/mL | Injection | 0.5 mg / mL | IV, IM |
| Dexmedetomidine hydrochloride 0.1 mg/mL | Injection | 0.1 mg / mL | IV, IM |
| Sileo 0.09 mg/mL dexmedetomidine Orion Corporation Equivalent to 0.1 mg/mL hydrochloride. Calibrated syringe; use within 4 weeks after opening. Canine chart-based dosing must not be replaced by arbitrary gel volumes. | Oral Gel | 0.09 mg / mL | OTM |
Monitoring and Administration
Monitor ECG, blood pressure, respiration and temperature. Reduce other anesthetic requirements to effect.
Avoid skin exposure; wear gloves when administering gel. Gel must contact gingiva, not be swallowed.
Atipamezole reverses alpha-2 effects; reversal dose depends on species and the actual dexmedetomidine amount, not a universal volume ratio.